It might not be long until Mahmoud Ahmadinejad's presidential term comes to an end but he doesn't seem to believe it will finally happen. During a recent interview on state television in which a journalist mentioned that his presidency would finish within a year, the president interjected, laughing: "How do you know?"

Under Iranian law Ahmadinejad cannot run for a third term, and on Friday officials announced the next election would be held on 14 June 2013. The last was in 2009 when Ahmadinejad took office for a second term amid allegations of fraud and unrest.

The president's joking response prompted speculation that he planned to preserve his dwindling power by grooming someone in his inner circle as his possible successor. Ahmadinejad's opponents pointed the finger at his close confidant and chief of staff, Esfandiar Rahim Mashaei, as a likely candidate.

Mohammad Dehghan, who sits on the parliament's executive board, criticised Ahmadinejad and accused him of pursuing a Putin/Medvedev-style reshuffle.

"Ahmadinejad should know that Iran is not Russia and he is not Putin. Ahmadinejad's Medvedev [a reference to Mashaei] has no position among the public opinion and he will not have any position in future," he said, according to the semi-official Mehr news agency. The president's office denied suggestions that Mashaei would put his name forward for the presidency.

Mashaei fell foul of conservatives after a power struggle last year between supporters of Ahmadinejad and those close to the supreme leader, Ayatollah Ali Khamenei. Khamenei's supporters believe that the confrontation stemmed from the increasing influence of Mashaei, an opponent of greater involvement of clerics in politics, whom they described as the head of a "deviant current" within the president's inner circle.

Speculation is rife about who will be Ahmadinejad's successor. Tehran's mayor, Mohammad-Bagher Ghalibaf, is one name often mentioned. Another is Saeed Jalili, the chief nuclear negotiator and a close ally of Khamenei. Many also tip Ali Larijani, the parliamentary speaker.